M.-Y. Lin

Insights on the Dusty Torus and Neutral Torus from Optical and X-Ray Obscuration in a Complete Volume Limited Hard X-Ray AGN Sample

We describe a complete volume limited sample of nearby active galaxies selected by their 14?195 keV luminosity, and outline its rationale for studying the mechanisms regulating gas inflow and outflow. We also describe a complementary sample of inactive galaxies, selected to match the host galaxy properties. The active sample appears to have no bias in terms of active galactic nucleus (AGN) type, the only difference being the neutral absorbing column, which is two orders of magnitude greater for the Seyfert 2s. In the luminosity range spanned by the sample, ?43.7, the optically obscured and X-ray absorbed fractions are 50%?65%. The similarity of these fractions to more distant spectroscopic AGN samples, although over a limited luminosity range, suggests that the torus does not strongly evolve with redshift. Our sample confirms that X-ray unabsorbed Seyfert 2s are rare, comprising not more than a few percent of the Seyfert 2 population. At higher luminosities, the optically obscured fraction decreases (as expected for the increasing dust sublimation radius), but the X-ray absorbed fraction changes little. We argue that the cold X-ray absorption in these Seyfert 1s can be accounted for by neutral gas in clouds that also contribute to the broad-line region (BLR) emission, and suggest that a geometrically thick neutral gas torus co-exists with the BLR and bridges the gap to the dusty torus.

Obscuration in active galactic nuclei: near-infrared luminosity relations and dust colors

We combine two approaches to isolate the AGN luminosity at near-IR wavelengths and relate the near-IR pure AGN luminosity to other tracers of the AGN. Using integral-field spectroscopic data of an archival sample of 51 local AGNs, we estimate the fraction of non-stellar light by comparing the nuclear equivalent width of the stellar 2.3 m CO absorption feature with the intrinsic value for each galaxy. We compare this fraction to that derived from a spectral decomposition of the integrated light in the central arcsecond and find them to be consistent with each other. Using our estimates of the near-IR AGN light, we find a strong correlation with presumably isotropic AGN tracers. We show that a significant o set exists between type 1 and type 2 sources in the sense that type 1 sources are 7 (10) times brighter in the near-IR at logL MIR = 42.5 (logL X = 42.5). These o sets only become clear when treating infrared type 1 sources as type 1 AGNs. All AGNs have very red near- to mid-IR dust colors. This, as well as the range of observed near-IR temperatures, can be explained with a simple model with only two free parameters: the obscuration to the hot dust and the ratio between the warm and hot dust areas. We find obscurations of A hot = 5::: 15 mag for infrared type 1 sources and A hot = 15::: 35 mag for type 2 sources. The ratio of hot dust to warm dust areas of about 1000 is nicely consistent with the ratio of radii of the respective regions as found by infrared interferometry.

Thick discs, and an outflow, of dense gas in the nuclei of nearby Seyfert galaxies

We discuss the dense molecular gas in central regions of nearby Seyfert galaxies, and report new arcsec resolution observations of HCN(1-0) and HCO

Constraints on the broad-line region properties and extinction in local Seyferts

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LLAMA : normal star formation efficiencies of molecular gas in the centres of luminous Seyfert galaxies

(1-0) for 3 objects. In NGC 3079 the lines show complex profiles as a result of self-absorption and saturated continuum absorption. H

The role of host galaxy for the environmental dependence of active nuclei in local galaxies

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Role of active galactic nuclei in the luminous infrared galaxy phase at z ≤ 3

CN reveals the continuum absorption profile, with a peak close to the galaxys systemic velocity that traces disk rotation, and a second feature with a blue wing extending to

BAT AGN Spectroscopic Survey - VIII. Type 1 AGN with massive absorbing columns

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LLAMA : nuclear stellar properties of Swift-BAT AGN and matched inactive galaxies.

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Fueling active galactic nuclei. II. Spatially resolved molecular inflows and outflows

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